The invention relates to a metering pump and in particular to a metering pump comprising a pump chamber with a diaphragm pump for delivery to a metering point and for the comprising of venting means in a return conduit connected to the outlet of the metering pump.
Such a metering pump is known from the German Patent No. 36 31 984. In this known metering pump the venting means is closed shortly before the beginning of the pressure stroke and opened shortly after the end of the metering stroke. A pressure valve is provided in the return conduit. As a consequence, the return flow is not exactly defined.